1. Field of Invention
This invention relates to providing systems and methods for utilizing local number portability (LNP) features to implement telephone number mapping (ENUM—tElephone NUmber Mapping).
2. Description of Related Art
ENUM establishes a way to link telephone numbers to the Global Internet. This concept can provide a way to reach multiple communication services using a single phone number. For example, one telephone number can provide a means to contact a user via phone, fax, email, pager, mobile phone, SIP (session initiation protocol) telephony address, website or any other resources that can be described by an internet addressing scheme.
ENUM is a standard adopted by the Internet Engineering Task Force (IETF) that uses the domain name system (DNS) to map telephone numbers to web addresses or uniform resource locators (URL) or other final handling or treatments. The goal of the ENUM standard is to provide a protocol which will provide for single number access to replace multiple numbers and addresses for an individual'. Handling treatments can include terminations to home phone, business phone, fax, cell phone, email and other communication devices.
ENUM is a convergence of the PSTN (public switched telephone network) and IP (internet protocol) networks. This method involves the mapping of a telephone number from the public switched telephone network to internet functionalities.
The E.164 standard details the components of the numbering structure and digits required to successfully route calls through the PSTN. For example, using a ten digit NANP (North American Numbering Plan) telephone number as an example (1-404-123-4567), the ENUM numbering scheme converts the number into a DNS entry as 7.6.5.4.3.2.1.4.0.4.1.e164.arpa.
One of the key functions of the ENUM protocol is the indication of naming authority pointer records (NAPTR) that define the service field options that can be associated with a particular telephone number. When an ENUM enabled phone call is placed, a session is initiated through the IP network to the ENUM Server. A lookup is performed in the ENUM registry database where an authoritative name server is then defined via the NAPTR information attached. The seamless end-point indicated by the NAPTR can lead to a telephone device, fax machine web site, cell phone, or email address as defined by the host party of the telephone number.
In the current communications environment, it will thus be appreciated that local number portability (LNP) allows customers to keep the same telephone number as they change service providers and technologies.
In the wireless and wire-line environments, LNP makes available Service Provider Portability (SPP), which allows the customer to change wireless/local service providers while retaining the same telephone number. For instance, one could switch wireless phone carriers (from Verizon to Cingular) without a change in their number. In addition, Service Provider Portability allows a user to be initially issued a landline number and later transfer that number to a wireless phone upon establishing a wireless account; or vice versa.
In addition to Service Provider Portability, LNP also provides Service Portability, which means that the type of service (i.e., plain old telephone service (POTS) to integrated service digital network (ISDN) service) can be changed without changing the user's telephone number.
With the implementation of the ENUM and LNP services, the telephony world has become extremely robust and adaptable to the changing needs of customers. However, because of their current implementations, there are many additional advantages inherent to each of them that could be further advanced should a system and method be devised that could efficiently provide the ENUM specification in an LNP (POTS) environment.
The current methods used to provide an ENUM specification in the LNP (POTS) environment is cumbersome and inefficient. In the examples disclosed herein, it should be appreciated that the terminating office uses a different LSP (local service provider) than the originating office. Otherwise, the originating office could be directly connected to the LSP of the terminating office if a call was placed intra-LATA (local area transport).
As shown in FIG. 1 and in accordance with the prior art, a call is placed from the originating telephone 105 to the terminating telephone 140. The call is initially forwarded to an originating office 110. Upon receipt of the call, the originating office 110 performs digit analysis on the dialed digits to determine how to route the call. A portion of this digit analysis can compare the dialed number against a routing table. The routing table contains information that indicates whether the dialed number is portable or direct dialed. The routing table indicates the preferred switching sequence to which the call is then routed. Of course, the actual switching sequence used may be altered due to technical problems along the sequence (for example, extremely high call volume, inoperable equipment, etc.)
If the dialed number is listed in the routing table as direct dialed, the call is sent directly from the originating office 110 to the terminating end office 125 through the switching sequence indicated by the routing table. At the terminating end office 125, a request is sent to a media gateway 130 to determine which NAPTR functions are available for that number. Based on the available functions, the call is forwarded to the appropriate server, reformatted, and sent to the telephone 140 or another designated device, such as an IP phone or a voicemail platform. It should be appreciated that the telephone 140 is only exemplarily depicted and can be any device addressable by the functions defined by the NAPTR entry. More particularly, the telephone 140 can be any device capable of being addressed using an internet addressing scheme, including a POTS telephone, an IP phone, fax, email, pager mobile phone, SIP (session initiation protocol) phone, or web server (website). Thus, the format of the call can then be amended according to the type of device the telephone 140 is.
If the called number is deemed portable and the terminating end office 125 does not reside on the switch controlling the originating office 110, the originating office 110 sends an LNP request across the STP (signal transfer point) 115 to the LNP database 120 based on the dialed digits. A lookup is performed at the LNP database to determine the appropriate routing sequence for the portable number and LNP database returns the response to the originating office 110 to handle the call based on the returned response. Once the call is handled based on the response, the call is routed and received at the terminating end office where an ENUM lookup is performed as described above. Subsequently, the call-flow continues to connect the call.
With the current method, numerous steps that are performed could be combined to free system resources and load. With the current configuration and its many steps, numerous steps and system resources could cause problems. Thus, the inventors have discerned that there is a need to merge these technologies in manner that they could be implemented together while efficiently providing the seamless advantages of ENUM and the versatility of LNP.